Motor-meter for alternating currents.



R. C. LANPHIER & J. H. HODDE. MOTOR METER FOR-ALTERNATING GURRENTS.APPLIGATION FILED JULY e, 1908.

91 0,550. V Patented Jan. 26,1909.

UNITED srnrns rgrnnr orrron ROBERT C. LANPHIER AND JACOB H. HODDE, OFSPRINGFIELD, ILLINOIS, ASSIGNORS SANGAMO ELECTRIC COMPANY, OFSPRINGFIELD, ILLINOIS, A CORPORATION OF ILLINOIS.

Application filed July 6,

To all whom it may concern:

Be it known that we, ROBERT C. LAN- 'PHIER and JAooB II. HoDnE, citizensof the United States, residing at Springfield, in the county of Sangamonand State of Illinois, have invented certain new and useful Improvementsin Motor-Meters for Alternating Currents, of which the following is aspecification, reference being had to the accompanying drawing.

Our invention relates to improved motor meters of the mercury type foralternating currents, and particularly to im rovenients. in the metershown and describec in Letters Patent to Robert C. Lanphier, No.843,155, of February 5, 1907, and its principal obj eat is to provide anew and improved mechanism for overcoming or compensating initialfriction so that the meter may run accurately on very light load.

In the mercury meter shown in the Letters Patent to Lanphier abovereferrrd to, the torque or rotative effect is produced by the action ofa magnetic field varying with the load current upon a largevolume ofcurrent pass ing across the armature and-derived from the secondary of alow potential step-down trans: former whose primaryis connected acrossthe main circuit. In the meter shown in that patent, devicesfor initialfriction compensation are shown, and which consist of an auxiliarysecondary circuit derived from the trans former whose main secondarywinding energizes the disk circuit and having in series with it. severalauxiliary turns around the magnet and an adjustable resistance wherebythe amount of current required for initial or light load compensationmay be adjusted. One difficulty with this .style of device forcompensating for initial friction lies in the fact that a large amountof resistance is required to get a range of compensation extending fromthe desired maximum to a very low value. If, therefore, a meter shouldbe adjusted to a given voltage,say 1 10 volts so as to have initialfriction properly compensated to give the meter accurate results on alight load, this meter would probably be too fast in case there was aconsiderable rise in the voltageand would cree on no load as 1t 1stermed. This form 0 device s then likely .to make it difficult to reducethe compensating effect as desired.

The object of our present invention is to Specification of LettersPatent.

Patented Jan. 26, 1909.

1908. Serial No. 442,101.

Referring to the drawing :2 indicates the is formed preferably of a bodyportion 3- of insulating material and a bottom plate 4 of non-magneticmaterial, so shaped as to inclose a chamber 5 adapted to contain mercuryand within which revolves a disk 6 mounted on a spindle 7 and providedwith a brake-disk 8 and braking magnets 9, and return plate 10, all ofwhich are of the wellknown and approved form and construction.

11 indicates a U-shaped magnet of soft iron, preferably formed of anumber of thin plates The magnet 11 is secured below the plate fl: inany well-known manner.

12 indicates the supply transformer of the system to which the meter isconnected.

13 indicates the main load circuit, and 141 the translating devices inthe circuit.

15 16 indicate windings which pass in portions of theU-shaped magnet 11and are connected in series with the load circuit 13.

17 indicates the primary of a low potentialstep-down transformer whichis connected across the main circuit 13.

21 indicates a few turns of i ductive winding introduced into thesecondary circuit of Patent above-named.

The devices so far described operate n the manner set forth in theabove-named Leta ters Patent to Lanphier, and their operationexplanation here.

\22 indicates another secondary-winding body or chamber-casing of themeter which 18 indicates a secondary of the trans will be readilyunderstood without further opposite'directions around the two verticalthe transformer in series with the armature and adapted to be variedin-any wellknownway for the purposes described in the Letters consistingof a fewturns of comparatively large wire around the primary winding 17.The circuit from this transformer divides at 23 into two wires 24*25,each of which passes with one or two turns in relatively oppositedirections around one leg of the gagnet 11, as is diagrammatically shownin i 1.

56 indicates a bar of metal having high conductivity, to one end ofwhich is connected the wire 27 which passes to the other end of thesecondary 22.

28 indicates a bar of resistance metal, to one end of'which is connectedthe wire 24 and to the other end the wire 25.

29 indicates a slide-block of metal of high conductivity which slidesupon the bars 26 and 28. It will be obvious that bysliding theslide-blool 29 in one direction or the other, the proportion of theresistance metal between the slide-block and the ends to which the wires24 and are connected will. be varied, and thereby the relative amountsof current which pass through the windings n the wires 24 and 25 aroundthe electromagnet will be correspondingly varied. If,

, for instance, the slide-block is moved as far as possible to the-left,the greatest possible amount of current will pass through the winding onthe wire 25 and the least possible through the winding on the wire 24,which willnause the maximum magnetization of the magnet and themaximumfield, which, co-

operating with the current passing across the disk from the secondary ofthe transformer,

will produce a torque in the direction in which is adapted to bedrivento measure By moving the slide-block 111 the its will be lesseneduntil, when the slide l; ociris the electrical centerof the dividedcircuit, the currents will exactly balance each other and nomagnetization be produced. By moving the slide-block past the electricalcenter, towards the right, let us suppose, the current in wire 24 willexceed the current in the wire 25 and the reverse magnetic e fect andthe reverse torque be pro (:luced fIt is evident from this thata maxi-.mum agnetlcefi ect can be produced either in can 2 rotation forward orbackward on low load, and that with the slide-block in intermediateposition so that the resistance of the t'w'oexciting windings is equalthere will be no light load or friction compensating effect. This methodof adjustment gives a very Wide range so that the meter can be set forany desired voltage without difficulty, and at the same time do awaywith the necessity for a large amount of resistancein the adjustment toobtain the desired result.

That which we claim as our invention, and desire to secure by LettersPatent, is,

1. In an alternating current meter having an energizing winding var ingwith the load current, and an induced ow potential current proportionateto the circuit pressure passing through the armature, the combinationwith the primary of a transformer connected across the load circuit, ofa secondar on said transformer, a twobranch circuit leading from saidsecondary and having auxiliaiy windings passing around the load excitingmagnet in opposite directions, and an adjustable resistance interposedin the circuit of said secondary whereby the volume of current flowingthroughsaid divided circuit may be varie 2. In an alternating currentmeter having a field energizing winding varying with the load currentand an induced low potential current proportionate to the circuitpressure passing through the armature, the combination with a primarytransformer connected across the load circult, of a secondary on saidtransformer, a circuit from said secondary having two auxiliary excitingwindings for the energizing magnet passing around the rent proportionateto the circuit pressure and passing through the armature, thecombination with a primary transformer connected across the load circuitof a secondary on said transformer, two auxiliary exciting windingspassing around said magnet in opposite directions and leading from oneend of said secondary, a resistance bar connected near its ends to saidauxiliary windings respectively, a second bar of high conductivityadjacent to said resistance bar and connected at one end to the-otherend of said secondary, and a conductor slide-block-connecting saidresistance bar. and said second bar.

ROBERT o. LANPH'IER. JACOB n. HODDE.

Witnesses:

FRANK; PRIDE, ALBERT D. BIRNBAUM.

